What happens when you take prednisone with licorice?
Real licorice root contains glycyrrhizin (glycyrrhizic acid), and it sets off a chain of events that quietly amplifies prednisone's effect on your blood pressure and potassium. Here is the sequence:
- Glycyrrhizin is broken down in the gut to glycyrrhetinic acid, the form that drives the interaction.
- Glycyrrhetinic acid blocks an enzyme called 11-beta-hydroxysteroid dehydrogenase type 2 (11-beta-HSD2). This enzyme normally inactivates cortisol — and prednisolone, the active form of prednisone — at the mineralocorticoid receptor in the kidney.
- With the enzyme blocked, prednisolone and cortisol activate those receptors as if they were aldosterone. The body behaves as though aldosterone levels are very high, even though they are not — a state called pseudohyperaldosteronism.
- Sodium and water are retained, blood pressure tends to rise, and potassium and hydrogen ions are excreted. The result can be low potassium (hypokalemia) and a metabolic alkalosis.
- Glycyrrhetinic acid also appears to slow the breakdown of glucocorticoids, which can raise circulating prednisolone levels and stretch out the steroid effect.
So licorice both prolongs and amplifies the mineralocorticoid side of prednisone. This is a well-characterised mechanism rather than a theoretical concern.
Why is this important?
Prednisone on its own has only weak intrinsic mineralocorticoid activity, so at usual anti-inflammatory doses it causes modest potassium loss. Add regular licorice intake and that modest effect can become clinically meaningful. The published literature includes case reports of patients developing severe hypokalemia, hypokalemic muscle weakness or paralysis, hypertension that resisted standard treatment, and cardiac arrhythmias after habitual licorice consumption — sometimes from everyday sources like candy or tea rather than supplements.
A practical problem is that many people do not realise their candy, herbal tea, cough drop, or traditional remedy contains pharmacologically active glycyrrhizin. Daily exposure adds up. Some chew licorice or eat black licorice candy regularly; others use licorice-containing herbal blends for cough, sore throat, or so-called adrenal support.
Risk is not the same for everyone. Older adults, people with cardiovascular disease, anyone already taking diuretics or laxatives, and those with reduced kidney function are the most vulnerable to dangerous potassium drops on this combination.
What should you do?
The core message is simple: keep real licorice and prednisone apart. Here is how that looks at each stage.
Before starting prednisone: Tell your prescriber about any licorice products you use — licorice root, black licorice candy made with real extract, licorice tea, herbal cough or throat blends, or traditional Chinese medicine formulas. Stop the licorice rather than starting the two together.
Every day while on prednisone: Skip real licorice in all its forms. Check ingredient lists, because licorice hides in cough drops, sore-throat blends, and adrenal-support supplements. If you want a licorice product for heartburn or digestion, deglycyrrhizinated licorice (DGL) has the active compound removed and does not cause this interaction — though it is still worth mentioning to your clinician.
After any change — and if symptoms appear: If you have been taking both, talk to your doctor or pharmacist about tapering off the licorice and whether to check your potassium and blood pressure. Get your potassium checked promptly if you notice muscle weakness, leg cramps, palpitations, swelling, or unexplained fatigue. Severe low potassium is a medical emergency.
Which specific products are affected?
Products that contain real licorice and therefore glycyrrhizin include:
- Black licorice candy made with licorice extract (for example soft Australian-style or Dutch "drop" licorice, and some black licorice brands)
- Licorice root herbal teas
- Licorice root powder and capsules from health food stores
- Herbal blends marketed for adrenal support, sore throat, or digestion
- Traditional Chinese medicine formulas containing gan cao (licorice root), often used as a harmonizing ingredient
- Some chewing gums, lozenges, and herbal cough drops with licorice flavoring
Most American red licorice candy is artificially flavored and does not contain glycyrrhizin — check the label. Anise-flavored products taste similar but contain no glycyrrhizin and are unrelated to this interaction.
Deglycyrrhizinated licorice (DGL) chewables, sold for heartburn and digestion, have the active compound removed and are acceptable during prednisone therapy.
The interaction applies across the glucocorticoid class — prednisone, prednisolone, methylprednisolone, hydrocortisone, and dexamethasone can all combine with licorice to amplify mineralocorticoid effects, with hydrocortisone particularly prone because of its higher native mineralocorticoid activity. Other potassium-lowering drugs can compound the risk: loop diuretics such as furosemide, thiazide diuretics such as hydrochlorothiazide, and amphotericin B.
The science behind it
The mechanism — glycyrrhetinic acid inhibiting 11-beta-HSD2 to produce pseudohyperaldosteronism — is established in the clinical literature.
A narrative review in Frontiers in Nutrition (Yoshino et al., 2021) summarises how glycyrrhizin metabolites drive licorice-induced pseudoaldosteronism and identifies the clinical risk factors, including older age, reduced kidney function, and co-administered potassium-lowering drugs. A case report in Clinical Case Reports (Je et al., 2025) documents a patient developing pseudohyperaldosteronism with severe hypokalemia and hypertension from licorice, illustrating that this is a real-world, not merely theoretical, problem. Interaction monographs (for example Drugs.com) specifically flag licorice plus prednisone, noting that glycyrrhizin can raise plasma prednisolone and potentiate corticosteroid effects and hypokalemia — directly reinforcing the additive risk when the two are combined.
Frequently Asked Questions
Is red licorice candy a problem with prednisone?
Usually not. Most American red licorice is artificially flavored and contains no glycyrrhizin. The concern is real black licorice made from licorice extract. Always check the ingredient list if you are unsure.
Can I use DGL (deglycyrrhizinated licorice) on prednisone?
Yes. DGL has the glycyrrhizin removed, so it does not cause the mineralocorticoid effect. It is acceptable during prednisone therapy, though it is still sensible to mention any supplement to your clinician.
How quickly can a problem develop?
It depends on how much licorice you consume and how often, plus your individual risk factors. Regular daily intake alongside prednisone can lead to meaningful potassium loss over days to weeks. Occasional small amounts are less concerning, but consistency matters more than a single serving.
What symptoms should make me check my potassium?
Muscle weakness, leg cramps, palpitations, swelling, constipation, and unexplained fatigue. If these appear — especially while you have been consuming licorice — get your potassium checked promptly, as severe hypokalemia is an emergency.
Does this apply to other steroids besides prednisone?
Yes. The interaction is shared across glucocorticoids, including prednisolone, methylprednisolone, hydrocortisone, and dexamethasone. Hydrocortisone is especially prone because it has more native mineralocorticoid activity.
What if I take a diuretic too?
That raises the risk. Loop and thiazide diuretics already lower potassium, and stacking them on prednisone plus licorice can compound the loss. Tell your clinician about all three if they overlap.
Key takeaways
- Real licorice contains glycyrrhizin, which blocks the enzyme that keeps prednisolone from acting like aldosterone — amplifying prednisone's sodium-retaining and potassium-wasting effects.
- Avoid real licorice (root, black licorice candy from extract, tea, herbal and TCM blends with gan cao) while on prednisone.
- Deglycyrrhizinated licorice (DGL) has the active compound removed and is acceptable.
- Most red licorice and anise-flavored products do not contain glycyrrhizin — check labels.
- Watch for muscle weakness, cramps, palpitations, swelling, and rising blood pressure; get potassium checked if they appear, and review your supplements with your doctor or pharmacist.